The communication tool is very important in any kind of collaborative environment. The type of communication depends on the situation, it could be email communication for mailing, Git or Subversion for version control, collaborative authoring needs wiki or Etherpad, shared task list for organizing the workflow, or full-fledged project management suite. Another tool that can be used for collaboration is team chat. The open source slack alternative can use team chat as a tool, wherein your colleagues who might be sitting in another room or in other city or country can communicate in real time which will enable the conversation to be faster, easier and will surely help in reducing confusion that often emerges due to asynchronous communications.
One needs to have complete concentration and uninterrupted space to work on important projects. By using the open source slack alternative one can use two collaboration tools, but the notifications are silenced so that you can check periodically when you take a break from your work.
The Slack has become famous among the software developing circles and leads to displacement of many tools. Slack is one of the closed sources of SaaS tool. The open source slack alternative will help you to ensure sole control over the communication between your team.